In the usage of modern computer systems and networks, the situation arises where systems having one proprietary protocol and data format are connected to systems having different data formats and protocols. Thus in order to provide for system integration in different networks, it is necessary that there be provided a system or method whereby the data formats of a first system can be transferred to and utilized by the network of a differently oriented system.
For example, the Unisys A Series computer systems involve a Central Processing Unit and memory together with storage such as disk storage which operates under the control of a Master Control Program. These A Series systems use a particular native format for the data files compatible with the A Series software which can be placed on CD-ROMS. Thus, the CD-ROMs which contain this A Series software contain an image of a formatted tape which can be utilized only by the A Series systems. However, when it is desirable to integrate a first system such as the A Series systems for operation with other platforms such as an NT system or a UNIX system, then problems arise in that the second system such as the NT system, utilizes formats which are not compatible with the software formats of the A Series system (first system).
In earlier operations, the software for a first system, such as an A Series system, was utilized by providing methods to burn CD disks from a Library Maintenance formatted tape. This method had the limitation in that it limited the type of files that were burned into the CD-ROMs to those of the "native A Series" files.
Now, in order to provide for system integration where a first platform, such as an A Series system, is to be coupled to a second platform such as a Microsoft NT system or a UNIX system, which integrated system would be designated as a Unisys ClearPath system, the desirability here would be to make and use a single CD-ROM disk which would carry both the A series software and at the same time carry the NT software.
Thus in this regard, a method is needed to couple the A Series files (with their native attributes) and also arrange them in a format capable of being stored on a particular media such as a CD-ROM which will also hold the readable software for the NT (or other) system.
The A Series systems have files with specialized attributes which are designated for example, as FILEKIND, CREATIONDATE, and RELEASEID, as indicated in the Glossary.
As a result, the Unisys A Series systems will provide a programmatic interface to its Master Control Program (MCP) which will provide a mechanism for "wrapping" and for "unwrapping" files.
"Wrapping" is a term which is used to define the process of packaging an A Series file, along with its Disk File Header information and a checksum (and optionally a digital signature), as a byte-stream data file, so that it can be transported across heterogeneous networks and non-A Series specific media, while still maintaining its native A Series attributes.
"Unwrapping" is a term used to define the process of taking a previously "wrapped file" and coupling it with the information from its original Disk File Header (DFH) in order to restore the original native A Series file, as it existed prior to being wrapped.
Thus, the problem of limitations in a software file format which is oriented to one system, can now be transformed in order to provide a format that is utilizable not just for a first system, but also for a first and second system, whereby the file format of the second system would not ordinarily be compatible with that of the first system.
One of the problems involved in the utilization of computer systems and personal computers has to do with the distribution of software. Once a customer has purchased or begun a license key, he is then able to make use of the Wrap and Unwrap commands. The code for these commands is in the Master Control Program (MCP). The Unwrap command is readily available to all Users. The Wrap command is enabled when the User applies the license key.
The Wrap/Unwrap feature makes software distribution easier for vendors who sell and distribute Unisys A Series software. It also enables A Series sites to store volumes of files off-line by wrapping them into containers, then copying the containers to a PC (personal computer) and then burning the container files on to a compact disk-ROM (CD-ROM). This provides an efficient system for storing old source files, object files and data files when archiving or retiring an old application system. This is also useful when archiving old files that are sometimes left by programmers on old disk families.
As described in the present disclosure, it is now possible to unwrap files from a compact disk (CD) using SW1 which is a software switch which is an additional option or parameter specified in the Unwrap statement. This can be accomplished by a Unisys A Series platform alone (first platform), or by an NT platform (second platform), in a network integrated with a Unisys A Series (first platform).
While the co-pending U.S. Ser. No. 962,468 provided a method for encoding (wrapping) a file or group of A Series files for transfer to another type of computer platform, then later, the "Unwrap" method algorithm shown herein, enables one to decode the file utilizing another A Series platform (first system) and restore the files to their original form. Thus, source files, data files, and code files can all be wrapped, copied, and later "unwrapped", using a single platform or an integrated platform, for subsequent usage. It should be noted that the encoding process preserves the original A Series file attributes of the file, which can later be decoded.
The method of providing native first system files, on a compact disk (CD) as a text byte stream data file, which is compatibly combined with industry standard text NT data files, and the subsequent usage of this text stream data file (on the compact disk, CD) by "unwrapping" the information from the CD, is done through two WFL (Work Flow Language) commands. Thus, the command to encode a file for transfer is called "WRAP". The command for decoding the particular file is called "UNWRAP".
The "encoding" process is called "wrapping the file", and the end result of the "WRAP" command is called a "wrapped file".
The "decoding" process is called "unwrapping the file" and the end result is the normal original first platform native file that one had originally started with on the first platform, such as the Unisys A Series platform.
There are two ways in which files can be wrapped. These include: (i) as stand-alone wrapped files; and (ii) in container files.
A "stand-alone wrapped file" contains a single file. It contains attribute information, verification information, and the data of the file itself.
A "container file" contains many files. It is similar, in concept, to a Library/Maintenance tape image as provided by Unisys Corporation. There is a directory part which describes the files in the container, and then the files themselves along with their respective headers follow this.
Files can be wrapped into either stand-alone files, or into container files. However, each one of these choices will have its own particular applications.
Files are always wrapped to Unisys A Series disk files. A wrapped file has a FILEKIND of WRAPPEDDATA.
A container file has a FILEKIND of CONTAINERDATA. These files are stored in a text stream format, which is ideally useful for FTP (File Transfer Protocol) in file transfer operations.
Wrapped files and container files can efficiently be transferred to other operating systems for storage on other media, particularly on CD-ROM's . When done properly, the files can be read directly back onto any Unisys A Series machines (first platform) by simply placing the compact disk (CD) into the A Series CD-ROM reader, and then "Unwrapping" the file or files from there. It is also possible to upload the wrapped file via file transfer protocol (FTP) to the user's A Series disk and "Unwrap" it from there as well. Similarly, in an integrated ClearPath Network involving a second platform (NT or UNIX) and first platform (A Series), the CD industry standard file can be unwrapped for utilization by the A Series platform and concurrently used to load the (NT or UNIX) system (second platform).
The present disclosure involves the "unwrap" operation, whereby there are provided methods giving the ability to restore files that were previously combined with their computer system attributes into text stream data files, and which were burned onto industry-standard CD-ROM disks for distribution.
This method and system allows a computer system user to restore the files from the burned CD-ROM disks without losing any of the information contained in the original attributes of the native system files, which had been converted into standard CD-ROM formatting.
Thus, a new flexibility for the distribution of software has been provided, whereby CD-ROMs which were burned with text stream data files involving both Unisys A Series data files, and also NT program and data files, can now be utilized in order to read-out, decode or "unwrap" the A Series files in a fashion which restores their native information and attributes for use by any Unisys A Series user system, while at the same time providing data to the NT system.